In the field of electronic non-impact printers, a number of different types of devices have been developed. These include laser printers, thermal printers, ink jet printers and the like. One such device that shows great promise is the light emitting diode (LED) printer. In such a device, an array of LEDs is positioned to address a photoreceptive surface so that when the latter is charged exposing the surface to light from the LEDs will discharge locations on the photoreceptor so as to produce an image composed of small dots of uncharged areas. The LEDs are enabled selectively by electronic drivers in response to a binary coded input to produce an image representative of information being transmitted. In a process known as reversed development, the image on the photoreceptor is developed by a toner material which may then be transferred to the record member.
As in any other system, the LED printer does have its problem areas. One such problem involves the materials from which LED arrays are produced. A chip, made of a material such as gallium arsenide (GaAs), is selectively doped to produce an LED site once anode and cathodes are connected to such doped sites. Such chips with LED sites are generally referred to as monoliths. These monoliths may be attached in tandem to a substrate, such as aluminum oxide, so as to produce an array of LEDs. The monoliths may be attached to the substrate by an adhesive such as epoxy resin. The monoliths must be laid next to one another in a rather precise fashion so that the cathodes of the respective modules are not so close as to short across one another. It is, therefore, necessary to have a relatively wide gap between epoxy areas when placing the LED monoliths directly on a substrate. Problems often arise because the ends of the monoliths are unsupported and, when wire bonded, will have a tendency to crack. Another problem that arises is that aligning the monoliths is difficult since they are required to be placed within .+-.0.0005 in. and moving them around causes the adhesive to move and create shorts. A still further problem is that replacement of a defective monolith is difficult because of the brittle nature of the gallium arsenide material from which the monoliths are made. As is well known, such material has a tendency to readily fracture.